Packaging System for Radioactive Waste

ABSTRACT

A method of packaging a radioactive waste including the steps of: (a) providing a containment enclosure having (i) an outer polymeric fabric layer and (ii) an inner polymeric fabric layer, wherein the outer and inner polymeric fabric layers are thermally stable to −40° F.; (b) placing a radioactive waste within the inner polymeric fabric layer; and (c) closing an outer closeable flap on the outer polymeric fabric layer.

BACKGROUND OF INVENTION

The present invention relates to methods and apparatuses for packagingor containerizing low level radioactive-containing materials inpreparation for transportation and disposal.

Low-level radioactive waste includes items that have become contaminatedwith radioactive material or have become radioactive through exposure toneutron radiation. This waste typically consists of contaminatedprotective shoe covers and clothing, wiping rags, mops, filters, reactorwater treatment residues, equipment and tools including nucleardecommissioning materials such as contaminated sand, soil, gravel andconstruction debris, luminous dials, medical tubes, swabs, injectionneedles, syringes, and laboratory animal carcasses and tissues. Theradioactivity can range from just above background levels found innature to very highly radioactive in certain cases, such as parts frominside the reactor vessel in a nuclear power plant. Low-level waste istypically stored on-site by licensees, either until it has decayed awayand can be disposed of as ordinary waste, or until amounts are largeenough for shipment to a low-level waste disposal site in containersapproved by the Department of Transportation.

These types of low-level radioactive contaminated materials aregenerally disposed of in landfills, but the contaminated solid materialshave to be properly “packaged” for disposal to reduce the potential forspread of contamination by leachate. While the materials of concern aresolid materials (as opposed to liquid), some entrained liquids may bepresent in the materials. In the following, the materials are understoodto be such solid low level radioactive contaminated wastes (“LLW”) asclassified by the Department of Energy (DOE) and the Nuclear RegulatoryCommission (NRC). See for example, 49 CFR § 171.8 et seq.

The US Department of Transportation (DOT) and the International AtomicEnergy Agency (IAEA) have approved, respectively, the Type A andIndustrial Package 3 (IP-3) packaging for transport of LLW. Type Apackaging is used to transport small quantities of radioactive materialwith higher concentrations of radioactivity and the IP-3 is used to shipwastes in which the radioactive material is distributed throughout asolid or a collection of solid objects, or is essentially uniformlydistributed in a solid compact binding agent (such as concrete, bitumen,ceramic, etc.). These packages are typically constructed of steel. TypeA and IP-3 packaging and its radioactive contents must meet standardtesting requirements designed to ensure that the package retains itscontainment integrity and shielding under normal transport conditions.Requirements for Type A and IP-3 packaging are addressed in 49 CFR173.412. Type A and IP-3 Packages must withstand moderate degrees ofheat, cold, reduced air pressure, vibration, impact, water spray, drop,penetration, and stacking tests. Type A and IP-3 Packages are not,however, designed to withstand the forces of an accident. Theconsequences of a release of the material in one of these packages wouldnot be significant since the quantity of material in this package is solimited. Type A and IP-3 packaging are only used to transportnon-life-endangering amounts of radioactive material. As used herein,“LLW” is distinguished from “Mixed Waste” which is a mixture ofradioactive waste and “hazardous” waste (i.e., a waste classified ashazardous for reasons other than radioactivity). LLW will be waste whichis not considered as hazardous by regulatory authorities for anycharacteristic other than radioactivity.

SUMMARY OF SELECTED EMBODIMENTS

One embodiment of the invention is a containment enclosure having a duallayer outer polymeric fabric combination including (i) a first polymericlayer, and (ii) a non-woven second polymeric layer thermally stable to−40° F. The enclosure further has an inner polymeric fabric combinationpositioned within the outer polymeric fabric combination, the innerpolymeric fabric combination including (i) a substantially impermeablethird polymeric seal (IPS) layer, and (ii) a non-woven fourth polymericlayer.

Another embodiment is a method of packaging a radioactive waste. Themethod first provides a containment enclosure comprising (i) a duallayer outer polymeric fabric combination including (1) a first polymericlayer, and (2) a non-woven second polymeric layer; and (ii) an innerpolymeric fabric combination positioned within the outer polymericfabric combination, the inner polymeric fabric combination including (1)a substantially impermeable third polymeric seal (IPS) layer, and (2) anon-woven fourth polymeric layer; wherein the first, second, third, andfourth polymeric layers are thermally stable to −40° F. Then a low levelradioactive waste (LLW) is placed within the fourth layer of the innerpolymeric fabric combination; and finally, an outer closeable flap onthe outer polymeric fabric combination is closed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a perspective view of one embodiment of the containment bagor enclosure of the present invention having a U-shaped zipper.

FIG. 1B shows the containment bag of FIG. 1A, but with closing flapsopen and the inner polymeric fabric combinations partially removed fromthe containment bag.

FIG. 2A is a perspective view of another embodiment of the containmentbag or enclosure having a center zipper.

FIG. 2B shows the containment bag of FIG. 2A, but with closing flapsopen and the inner polymeric fabric combinations partially removed fromthe containment bag.

FIG. 3 shows a series of polymeric layers for a first embodiment of thecontainment bag.

FIG. 4 shows a series of polymeric layers for a second embodiment of thecontainment bag.

FIG. 5 shows a series of polymeric layers for a third embodiment of thecontainment bag.

FIG. 6 shows a series of polymeric layers for a fourth embodiment of thecontainment bag.

DETAILED DESCRIPTION

Many embodiments of the present invention relate to enclosures or bagsformed of one or more polymeric textiles or fabrics. These polymeric“fabrics” can be any sheet-like polymeric materials produced byvirtually any technique, including both woven polymeric fabrics andnonwoven polymeric fabrics. Woven polymeric fabrics typically consist ofmonofilament, multifilament, slit-film and/or fibrillated slit-filmyarns that are woven into a fabric on conventional fabric weavingmachinery using a wide variety of traditional, as well as proprietary,weaving patterns. Nonwoven polymeric fabrics consist of fibers that arecontinuous filament or short staple fibers. These fibers are then bondedtogether by various processes that can include a needling process thatintertwines the fibers physically (needlepunched), or a chemical/thermalbonding operation that fuses adjacent fibers together.

In many instances, polymeric “coatings” or “films” will be applied toone surface or the other (or both surfaces) of polymeric fabrics.Polymeric “coatings” are normally created by applying a thin layer ofmolten coating polymer to another surface, e.g., a polymeric fabric.Polymeric “films” are normally a separately formed thin layer ofpolymeric material which is then adhered to (e.g., laminated onto) thesurface of another material (such as a polymeric fabric).

A particular polymeric fabric will sometimes be characterized as havinga certain weight or mass per unit area, typically in terms of ounces persquare yard, for example, a 12 oz/yd² non-woven polypropylene, which maybe shortened to “12 oz” non-woven polypropylene (the area dimensionbeing understood if not stated). However, at other times, a polymericfabric may simply be described in terms of its thickness, e.g., 12 milreinforced polyethylene or a 3 mil polyethylene coating. Althoughpolymeric fabrics may be described in terms of either mass per area orthickness, those skilled in the art can readily convert between theseunits for a given material.

Often containers or bags formed of polymeric fabrics will includemultiple discrete layers of the same or different materials. In many ofthese multi-layer bags, each layer is in essence a separate bag and mayhave a sidewall, a top portion, a bottom portion, a top edge (where thesidewall meets the top portion), and an opening flap (or flaps) alongthe top portion. The final assembled product results in a nested seriesof bags or layers. These bags may or may not be joined together, such assewn together, heat welded together or adhesively bonded. Alternatively,it may be the case that one or more of the layers will be sewn or bondedtogether before being formed into the bag shape. One or more of thelayers may have individual closing mechanisms, for example a zipper, ora “ziplock” type of closure device. Often, it is advantageous that eachlayer can be opened and closed independently from the other layers. Somepreferred constructions have zippers (including ziploc type of toothlesszipper closures) which traverse down the center of the top portion ofeach bag, much like the closable opening shown in U.S. Pat. No.8,894,282, which is incorporated by reference in its entirety.Alternatively, the zipper may be along three sides of a rectangularclosing flap (i.e., a “U-shaped” zipper) as shown in U.S. Pat. No.8,777,034, which is also incorporated by reference in its entirety.Additionally, cardboard inserts may sometimes be provided to line theinterior sidewalls to allow the assembled product to be self-standing.

FIGS. 1 and 2 illustrate one embodiment of containment enclosure orcontainment bag 1. In these embodiments, containment bag 1 isrectangular in shape with a width “w” of 5.5′, a length “l” of 8′, and aheight “h” of 5.5′. Naturally, the shape and dimensions of containmentbag 1 could vary greatly depending of the particular applicationrequirements, with volumes of the containment bag as small as 1 yd³ oras large as 40 yd³ (including any sub-range in between).

FIGS. 1A and 1B also show this embodiment of containment bag 1 having aseries of lifting straps 35 positioned on the outer surface ofcontainment bag 1 and extending from one sidewall 3 of the bag to theopposing sidewall 3 of the bag (and likewise one end wall 4 to theopposing end wall 4). It can be seen that the lifting straps 35 haveattachment loops 36 on each end which typically extend above the bagsidewalls. Lifting straps 35 will be held in place by strap retainers37, but the lifting straps can slide within strap retainers 37, much asdescribed in U.S. Pat. No. 9,365,345, which is incorporated byreferences herein in its entirety. FIG. 1A suggests how a top closing(outer layer) flap 5 includes a U-shaped or three sided zipper 6 (shownin the closed position). One preferred zipper is a #10 coil nylonzipper, with two pulls positioned on the zipper tracks. However, otherzipper sizes or zipper types could also be used.

In certain preferred embodiments, containment bag 1 is constructed toinclude an outer polymeric fabric combination and an inner polymericfabric combination. FIG. 3 illustrates one example of fabric layerswhich could form this inner and outer fabric combination. The outerfabric combination includes a first polymeric layer 50 and a 6 to 45 oz(or any subrange in between) non-woven second polymeric layer 55, wherethe second polymeric layer 55 is thermally stable down to −40° F. Thesecond layer is “thermally stable” in the sense that it does notsignificantly lose its strength characteristics or otherwise degrade attemperatures down to −40° F. First polymeric layer 50 and the non-wovensecond polymeric layer 55 are joined together with the nonwoven secondpolymeric layer oriented toward the interior of the bag (except for thetop closures of the two layers as explained in more detail below). Thetwo layers can be joined in any conventional manner, including sewing,laminating, heat welding or adhesive bonding. In the FIG. 3 embodiment,first polymeric layer 50 is a 12 to 30 mil thick woven polyethylene(WPE) layer 52 and second polymeric layer 55 is a 8 to 30 oz non-wovenpolyester (NWPET) layer. In a preferred embodiment, first layer 50 is 20mils and second layer 55 is 16 oz. FIG. 3 also suggests how first layer50 includes the 1 to 20 mil substantially impermeable coating or film 51formed on the WPE layer 52. In a preferred embodiment, this coating orfilm is a 3 mil polyethylene coating. The polyethylene coating or filmprovides an outer surface which is more easily wiped down anddecontaminated, i.e., contaminated particles are more likely to lodgebetween fibers on a woven or nonwoven surface than on a smoother coatingor film surface. In many embodiments, a polymer layer is considered“substantially water impermeable” (or alternatively simply “waterimpermeable”) when the layer is capable of passing a water spray testsuch as described in 49 CFR § 173.465 (which is incorporated byreference herein).

FIG. 3 also suggests how the inner polymeric fabric combination ispositioned within the outer polymeric fabric combination (i.e., theright side of the layers being toward the interior of the bag). Thisinner polymeric fabric combination includes the 4 to 30 milsubstantially impermeable third polymeric seal (IPS) layer 60 and the 6to 45 oz non-woven fourth polymeric layer 65. The IPS third layer 60 canbe formed of many different polymeric materials as long as thosematerials are substantially impermeable and are thermally stable down to−40° F. Non-limiting examples of acceptable IPS materials includepolyethylene and polyester. In a more preferred embodiment of the FIG. 3design, the IPS third layer is an 8 to 10 mil polyethylene layer and thefourth polymeric layer is an 8 to 30 oz (most preferably 16 oz)non-woven NWPET layer. FIG. 3 also suggests how in more preferredembodiments, the outer polymeric fabric combination (i.e., layers 52 and55) are joined to form a first bag-shaped enclosure. On the other hand,the space seen in FIG. 3 between layers 55 and 60, and between layers 60and 65, suggests how the IPS third layer forms a second, separatebag-shaped enclosure, and the NWPET fourth layer forms a third separatebag-shaped enclosure. The three bags formed by combined layers 50/55 andseparate layers 60 and 65 will be placed in a nested configuration assuggested by FIG. 1B. It will be understood that in many embodiments,all layers forming the containment enclosure (i.e., the overallmulti-layered bag) will be of materials which are thermally stable downto at least −40° F.

FIG. 1B also suggests how first (outer) layer 50 will not only includethe closing flap 5, but the second layer 55 will include its own closingflap 11 since the two layers are not joined along their closing flaps.Thus, closing flap 11 will include its own three-sided zipper 12, whichcloses in an opposing fashion to zipper 6. Although not explicitlyshown, IPS third layer 60 will have a center zipper which is preferablyair and water tight. Fourth layer 65 may or may not have a separatezipper closure. FIGS. 2A and 2B illustrate a similar containment bag 1,but having a center zipper 13 as described in U.S. Pat. No. 8,894,282referenced above. FIGS. 2A and 2B suggest how the closeable flaps 14 ofthe bag can be formed as extensions of sidewalls 3 and end walls 4, withthe zipper 13 extending along the perimeter of the closeable flap(s)which ultimately joins the flaps together down the top center of thebag. While the figures show zippers closing the closeable flaps of thecontainment bags, any conventional or future developed method of closingthe bag flaps could be employed, including as nonlimiting examples, tieclosures, Velcro® closures, or simply folding or “goose-necking” andtying off or taping the closable flaps 14 (with the procedure typicallybeing followed for the flaps of each layer forming a separate bag).

FIGS. 4 to 6 illustrate further layer combinations which could beemployed in creating containment bag 1. FIG. 4 suggests how the firstlayer is formed by nonwoven polymeric material 53 with coating or film51. In one example, the nonwoven polymeric material 53 is a 12 oznonwoven polyester (NWPET) layer with 3 mil polyethylene coating or film51. The NWPET layer 53 is then joined to 16 oz NWPET second layer 55. Aswith the FIG. 3 embodiment, the IPS third layer 60 may be an 8 to 10 milpolyethylene layer and the fourth layer 65 is a 16 oz NWPET layer.Again, third layer 60 and fourth layer 65 form separate bag-shapedenclosures.

FIG. 5 shows a different embodiment where layers 60 and 65 are notseparate bags, but all four layers 50, 55, 60, and 65 are joinedtogether forming in essence a single bag. As previously described, thelayers could be joined by any suitable conventional technique such assewing, heat welding, or adhesive bonding. FIG. 6 illustrates adifferent embodiment where a 3 mil polyethylene coating forms the firstlayer 50. In this embodiment, second layer 55 could be a 25 to 60 oz (orany subrange in between) nonwoven layer and in a preferred embodiment,is a 30 oz NWPET layer. IPS third layer 60 may be a 4 to 30 milpolyethylene layer and the fourth layer 65 may be a 8 to 30 oz NWPETlayer.

Although one embodiment of the present invention is a containment bag orenclosure apparatus, another embodiment is a method of using thecontainment bag. This method would generally include the steps of (i)providing a containment bag 1, placing a LLW material within the NWPETlayer of the inner polymeric fabric combination; and closing the one ormore closeable flaps on the different layers, e.g., separate nestedfabric bags. Although one embodiment of this method involves placing ofLLW material in the containment bag, other embodiments could involve theplacement of other types of radioactive wastes (e.g., those notconsidered “low level” radioactive wastes) in the above describedcontainment bags.

In certain method embodiments, the containment bag 1 is neither (i)positioned within an enclosed hardsided container by itself, nor (ii)positioned with an enclosed hardsided container within it. The polymercontainment bag may be considered a flexible or “softsided” container.An “enclosed hardsided container” is a container with rigid walls whichis enclosed on all sides, e.g., is not a container with an open top oran open side, and such enclosed hardsided containers are normally sizedto receive a single bag for permanent disposal in combination with thecontainer. For clarity, filling containment bags 1 with LLW material andthen placing multiple containment bags in a railcar or truck-trailer fortransportation would not be placing the bags inside a “enclosedhardsided container” because the railcar and truck-trailer are notdesign to hold a single bag nor to be disposed of with the bag.

This method could also include the steps of positioning containment bag1 in a load frame (e.g., a custom sized open metal box) or placing lightweight inserts (e.g., cardboard inserts) between the second and thirdlayers in order to provide rigid sidewalls allowing the bag to be“self-standing.” See for example, U.S. Pat. No. 9,478,322. A load frameis usually a rigid structure capable of holding the fabric containmentbag in an open position, but the frame structure is generally notcapable of completely enclosing the bag. For example, a constructiondumpster having no closeable top could be a load frame. A morespecialized load frame is the EZ Frame™ available from PacTec, Inc. ofClinton, La., but again, virtually any rigid structure capable ofholding the fabric containment bags in an open position may serve as aload frame.

The term “about” will typically mean a numerical value which isapproximate and whose small variation would not significantly affect thepractice of the disclosed embodiments. Where a numerical limitation isused, unless indicated otherwise by the context, “about” means thenumerical value can vary by +/−5%, +/−10%, or in certain embodiments+/−15%, or even possibly as much as +/−20%. Similarly, “substantially”will typically mean at least 85% to 99% of the characteristic modifiedby the term. For example, “substantially all” will mean at least 85%, atleast 90%, or at least 95%, etc.

1-17. (canceled)
 18. A method of packaging a radioactive wastecomprising the steps of: (a) providing containment enclosure comprising:(i) a dual layer outer polymeric fabric combination including (1) afirst polymeric layer, and (2) a 6 to 45 oz non-woven second polymericlayer, wherein the first polymeric layer and the non-woven secondpolymeric layer are joined together; (ii) an inner polymeric fabriccombination positioned within the outer polymeric fabric combination,the inner polymeric fabric combination including (1) a 4 to 30 milsubstantially impermeable third polymeric seal (IPS) layer, and (2) a 6to 45 oz non-woven fourth polymeric layer; and (iii) wherein the first,second, third, and fourth polymeric layers are thermally stable to −40°F.; (b) placing a low level radioactive waste (LLW) within the fourthlayer of the inner polymeric fabric combination; (c) closing an outercloseable flap on the outer polymeric fabric combination.
 19. The methodof claim 18, wherein the nonwoven second and fourth polymeric layers areoriented toward the interior of the enclosure.
 20. The method of claim18, wherein the first polymeric layer is a 10 to 30 mil thick wovenpolyethylene (WPE) layer with a 1 to 20 mil substantially impermeablecoating or film formed thereon.
 21. The method of claim 20, wherein thesecond and fourth polymeric layers are a 8 to 30 oz non-woven polyester(NWPET) layer.
 22. The method of claim 18, wherein (i) the firstpolymeric layer includes a 1 to 10 mil substantially impermeable coatingor film formed on the non-woven second polymeric layer and (ii) thenon-woven second polymeric layer is at least 10 oz.
 23. The method ofclaim 18, wherein the IPS layer is not attached to the nonwoven fourthpolymeric layer of the inner polymeric fabric combination.
 24. Themethod of claim 21, wherein the IPS layer is attached to the NWPETfourth layer of the inner polymeric fabric combination.
 25. The methodof claim 21, wherein (i) the IPS layer is attached to the NWPET fourthlayer of the inner polymeric fabric combination, and (ii) the IPS layeris attached to the NWPET second layer of the outer polymeric fabriccombination.
 26. The method of claim 18, wherein (i) the IPS layerincludes a closeable flap, and (ii) the outer polymeric fabriccombination includes a closeable flap.
 27. The method of claim 26,wherein the first and second layers of the outer polymeric fabriccombination have separate flaps with zippers.
 28. The method of claim27, wherein the fourth layer includes a zipper closure.
 29. The methodof claim 26, wherein the closeable flap on the outer polymeric fabriccombination includes a three-sided zipper and the closeable flap on theIPS layer includes a center zipper.
 30. The method of claim 29, whereinthe outer polymeric fabric combination and the IPS layer both include acenter zipper.
 31. The method of claim 29, wherein the outer polymericfabric combination and the IPS layer both include a three-sided zipper.32. The method of claim 18, wherein (i) the outer polymeric fabric formsa first bag-shaped enclosure, (ii) the IPS third layer of the innerpolymeric fabric combination forms a second bag-shaped enclosure, and(iii) the NWPET fourth layer of the inner polymeric fabric combinationforms a third bag-shaped enclosure.
 33. The method of claim 18, whereina plurality of lift straps positioned on an outer surface of thecontainment enclosure pass from one sidewall of the enclosure to anopposing sidewall of the enclosure, the lifting straps havingattachments loops on each end.
 34. The method of claim 18, wherein theIPS third layer is formed substantially from polyethylene or polyester.35. (canceled)
 36. A containment enclosure comprising: (a) an outerpolymeric fabric combination including (i) a 10 to 30 mil thick wovenpolyethylene (WPE) layer, and (ii) a 8 to 30 oz non-woven polyester(NWPET) layer, wherein the WPE layer and the NWPET layers are sewntogether; and (b) an inner polymeric fabric combination positionedwithin the outer polymeric fabric combination, the inner polymericfabric combination including (i) a 6 to 30 mil substantially impermeablepolymeric seal (IPS) layer, and (ii) a 12 to 30 oz non-woven polyester(NWPET) layer.
 37. The containment enclosure of claim 36, wherein theNWPET layers are oriented toward the interior of the enclosure.
 38. Thecontainment enclosure of claim 36, wherein (i) the outer polymericfabric forms a first bag-shaped enclosure, (ii) the IPS layer of theinner polymeric fabric combination forms a second bag bag-shapedenclosure, and (iii) the NWPET layer of the inner polymeric fabriccombination forms a third bag-shaped enclosure. 39-74. (canceled)